1. FIELD OF THE INVENTION
This invention relates to a safety needle guard for preventing inadvertent needle punctures or sticks and for rendering a syringe and needle assembly useless after one use by permanently fixing the plunger in the syringe body and capping the entire needle with the needle guard, by use of a fast acting adhesive contained in the needle guard.
2. BACKGROUND OF THE PRIOR INVENTION
In light of widespread abuse of syringes and needles by drug addicts and the recent spread of AIDS associated with the use of contaminated needles, the prior inventions proposed a syringe and needle assembly with various safety features. To prevent reuse of discarded disposable syringe and needle assemblies and for preventing inadvertent needle punctures, many types of safety devices have been proposed, for example, in U.S. Pat. No. 4,270,536 to Lemelson, U.S. Pat. No. 4,248,246 to Ikeda, U.S. Pat. No. 4,710,170 to Haber et al., U.S. Pat. No. 4,270,536 to Chen, U.S. Pat. No. 4,735,311 to Lowe et al., U.S. Pat. No. 4,801,295 to Spenser, and U.S. Pat. No. 4,872,552 to Unger.
U.S. Pat. No. 4,270,536 to Lemelson discloses a needle breaking device. Specifically, after using the syringe and needle assembly, a plunger portion of the syringe is taken completely out of the syringe. The head of the plunger has a hole for holding the needle in place during breakage. However, this method or device is not safe, in that, the fluid contained within the needle, which may be contaminated, becomes exposed to the person handling the syringe when the plunger is completely pulled out. Moreover, during the breaking process, the needle of the syringe may shatter, generating fragments which can stick the user and expose the user to potentially biohazardous material.
A second embodiment of the Lemelson patent discloses a sheath for encapsulating the needle by taking the plunger off the syringe and placing it over the needle. Again, because, the plunger has to be taken off the syringe, contaminated fluid in the needle can expose the user. Furthermore, this device does not disable the syringe as the plunger can be placed back into the syringe.
U.S. Pat. No. 4,248,246 to Ikeda discloses a cap for enclosing a needle portion of a sampling blood collector. The cap contains a seal material which is placed over the tip of the needle after its use. However, Ikeda does not offer sufficient protection against subsequent accidents because the cap can be easily pulled off.
U.S. Pat. No. 4,735,311 to Lowe et al. (Lowe) is substantially similar to the Ikeda patent, except that the Lowe patent relates to a syringe. A cap is used in the identical manner as the Ikeda patent to seal the needle and to prevent an inadvertent needle puncture.
U.S. Pat. No. 4,710,170 to Haber et al (Haber) discloses a syringe assembly for preventing an accidental needle puncture and for rendering the syringe inoperative. Specifically, the entire needle assembly can be pulled into the syringe body. The plunger is then pushed directly into the needle portion until the needle completely embeds into the plunger. While this device completely disables the syringe and prevents an accidental needle puncture once disabled, the shortcoming of this patent is that it cannot be used in conventional syringe and needle assemblies. On the other hand, the present invention is related to a protective sheath which can be used on any conventional assembly by simply capping the needle with the sheath as opposed to the elaborate steps required in the Haber patent. Also, the steps required in the Haber patent to disable the syringe may in some instances be too complicated for ordinary individuals to follow.
U.S. Pat. No. 4,728,321 to Chen discloses a syringe cap for disabling the syringe after one use. Specifically, a plug at the tip of the cap is slidable along the inner surface of the cap. By pushing in the plug, the needle will engage the tip portion of the needle to puncture the plug. Then, pulling the plunger causes adhesive contained within the plug to flow into the needle, thereby disabling the needle when the adhesive sets. The Chen patent has two drawbacks. First, the plug is easily pushed into the needle. Even a slight inadvertent push can cause the plug to engage the needle. The Chen patent provides no adequate measures for preventing the plug from being engaged accidentally. Second, the entire cap along with the plug can be pulled off, thereby exposing the needle for a possible needle injury Further, the Chen patent does not provide any means for disabling the syringe portion
U.S. Pat. No. 4,801,295 to Spenser discloses a sleeve which slides along the outer body syringe surface. When the sleeve is fully extended the needle is shielded, thereby avoiding an accidental needle puncture. While the sleeve is designed to be permanently locked in the extended safety position, as shown in FIGS. 6 and 18, the safety sleeve can be broken with force or can be severed from the syringe, thereby exposing the entire needle. Because the syringe and the needle are not disabled, the syringe and the needle can be reused.
U.S Pat. No. 4,872,552 to Unger discloses a safety cap which is hinged to a syringe and needle assembly. When using the assembly, the cap is first pivoted away from the needle portion. After using the assembly, the cap is placed back on the needle portion. The cap also includes a block slidably engaged therewith to enable the tip portion of the needle to penetrate the block, thus shielding the needle to prevent an accidental needle puncture. However, the shortcoming of the Unger invention is that the assembly is not disabled. Any one can remove the cap from the assembly and reuse the assembly.
Currently, used syringes and needles are first collected in mass quantities. Once collected they are destroyed or disposed of by one or several methods. For instance, needle chopper, autoclaving (deforming), and incineration have been used to destroy or dispose used syringes and needles. However, these methods are not entirely satisfactory, in that, the syringe and needle assemblies are not rendered useless immediately after their use. This provides an opportunity for individuals to pilfer syringes and needles during the collection of these discarded items. By providing a needle guard in the present invention to permanently and immediately render the syringe and needle useless, even if the discarded and disabled syringes and needles are pilfered during the collection for destruction, they cannot be reused.
The prior inventions do not provide a non-mechanical device for immediately rendering the syringe and needle completely inoperative by using adhesive in the needle guard. Rather, the prior inventions require a safety device to be part of the original needle assembly package and they are either of a mechanical locking nature or require force to break the needle portion of the syringe. None of the prior inventions encompasses the entire range of safety and permanence of the present invention which completely renders all functional parts of syringe inoperative.